This invention relates generally to shipping containers, and more particularly to shipping containers of corrugated fiberboard for shipping major household appliances such as washing machines, dryers, refrigerators, and food freezers.
Household appliances of these types are generally fairly large and may weigh several hundred pounds, so that the design of shipping containers for these appliances has received considerable attention to provide optimal packaging at minimal expense. Such containers have long been made of corrugated fiberboard in the form of a rectangular prism to allow easy fabrication of the containers as well as the use of automatic machinery to the greatest extent possible to minimize labor costs. Generally, a container comprises a tube portion consisting of four sidewalls which have flap extensions at the top and bottom of each side. The bottom flaps may be secured to a bottom cap, which is glued, stapled, or otherwise secured to the flaps, or the flaps themselves may be made sufficiently large to be folded over and glued or stapled together to form a bottom cap. Likewise, a separate top cap is supplied that is folded over and either glued or stapled, or secured by strapping around the periphery of the upper sidewall portions, to provide complete coverage of the appliance.
The sidewalls of the container must be heavy enough to protect the sidewall portions of the appliance from damage caused by penetration of the sidewalls during handling and shipping, and the containers must be strong enough to allow vertical stacking, often five or more high, to allow efficient usage of floor space in warehouses and in transport vehicles. Heretofore, the stacking and protection requirements have involved the use of corner posts at the four corner portions of the sidewall. These corner posts are generally made by folding several layers of corrugated fiberboard to form a thick, rigid, angular post that fits between the appliance corners and the container sidewalls to support the weight of appliances stacked on top of the particular container, and also to hold the sidewalls a spaced distance away from the walls of the appliance to minimize the effect of any penetration of the sidewalls during handling which might result in contacting and damaging the sidewalls of the appliance. The manufacture and installation of these corner posts have required substantial manual labor, since it is first necessary to place the tube portion of the container over the appliance, after which the corner posts must be carefully and precisely inserted by hand before the final closure can be made.
Another requirement for such containers is that the common method of handling, particularly in warehouses, utilizes a fork lift truck having a lifting member in the form of a horizontally extending, upwardly projecting blade which fits within a reinforced, folded portion of the top cap so that the appliance is lifted from the top without the need to have lifting forks inserted under the bottom, which would require leaving additional vertical spacing for the forks, as well as avoiding the damage caused by the projecting forks as the fork lift vehicle is maneuvered in the warehouse. Thus, in addition to the compressive strength of the tube portion, it is necessary to provide sufficient tensile strength that the appliance can be lifted by the top cap while its weight rests on the bottom cap, without any resulting damage to the appliance.